Modular belts and particular flat top modular belts are widely used for the transport of foodstuff with direct contact of the foodstuff with the conveying surface of the belt. Belts and equipment for such transport must be regularly cleaned in order to avoid contamination of the food with decomposed residual matters and bacteria.
The modules are usually constructed from plastics that are approved for direct contact with foodstuff. The modules typically have a closed, smooth surface that cleans well. The main area of difficulty is the hinge where the modules are connected together. The hinges typically have gaps where foodstuff can penetrate and become trapped. These residual deposits of foodstuff are difficult to remove. In order to address this problem, there have been designs that provide conical gaps that open when the belt modules move around a sprocket. One such design is shown in U.S. Pat. No. 6,725,883 which is assigned to the assignee of the present invention. Another design is shown in U.S. Pat. No. 5,706,934. These belt designs are further characterized by a smooth flat bottom side that is only interrupted by the links needed to connect the modules to form a belt. In most cases this type of belt is used in a bricklayed assembly of more than one module per module row. These bricklayed belts have small gaps where the module ends meet. In order to eliminate these gaps and as a further improvement in cleanability long modules were used to form a chain-like belt and to eliminate the bricklayed arrangement completely as shown in U.S. Pat. No. 6,758,329. Although the gaps between the module ends are eliminated, these long modules still suffer from a large number of gaps between the equally spaced interdigited links and therefore there was still room for improvement. A further improvement is possible by eliminating some of the links and therefore reducing the number of gaps between the side of the interdigited links. This design offers even better cleanability due to less hinge links but results in low belt strength. The strength reduction is not only caused by the reduction of the number of load transmitting links, but also by the large distance between links. The risk with such a design is the hinge pin, usually made from plastic, being bent between the wider, equally-spaced links and if under load (tension) results in a very flexible and less stable belt. Accordingly, there is a need for a belt module that improves cleanability while maintaining good belt strength.